Test structure for measurement of conductive film thickness

A top-contact-resistor test structure, measurements made to validate its operation, and supporting analysis for VLSI process monitoring are described. The structure was devised to simulate the ability of a Van de Pauw test structure to provide reliable local values of the sheet resistance of a conducting film but in a plane perpendicular, rather than parallel, to the wafer surface. The objective was to provide access to film thickness through electrical measurements in a manner similar to that in which the sheet resistance measurements obtained from Van der Pauw structures make linewidth measurements possible when used in conjunction with a Kelvin resistor. Resistance measurements performed with this test structure permit calculation of film thickness and bulk resistivity.